NEED HELP CLUNKING SOUND FROM REAR DIFF

[RickJC288]

So the other day I traded my old car for a 1990 nissan 300zx automatic non turbo. I test drove it and it was all good then a week later made the trade.

As I was driving it home on the freeway once I got past 55 60 I start to feel the rear end fish tail over bumps but never bottomed out. Front needs to be aligned cause it shakes then once I got home washed it and drove it for a little then this Clunky sound was coming the rear end? It only happens when I'm at a dead stop and then give it gas to get off. It stops at 15mph then comes back after 45?
Owner said he drifted and smashed the passenger rear rim and had a lower arm installed. What could the problems be?
I'm extremely new with this vehicle and need help!

[z.Leinbach]

is there any abnormal tyre wear? cupping, feathering and such? or is it more towords the seat area?? cause to me that seems more like a carrier bearing issue and traight. (i have a simmilar problem)

[centralcoaster33]

Clunking sounds can be the subframe shifting around, often felt on firm acceleration or decceleration. This is due to deteriorated sub-frame bushings. It could possibly be bad control arm bushings or even the differential bushings. Get under the rear end and have a look around. You can also see about moving your driveshaft to check for play at the carrier bearing, but that would be more of a vibration thing than a clunk or fishtail I think. Maybe the previous owners 'repairs' weren't done very well and things might be loose. If you can jack the car up, notice how the sub-frame moves separately from the chassis as you lift it, that will be a clue to what's loose, if anything.

Welcome to NicoClub and congrats on acquiring a cool car!

[RickJC288]

Well the inside of the tires have more wear and tear then the outside and the clunk sound and the feel of it feels to be on the right rear. But we lifted it up and put it in drive and gas some gas then stopped to see if the differential bearings were gone but it's moves but the sound isn't there? But while jacked up we cruised it to 40 (not the safest idea but have to do what you have to) and at the speed my buddy said the tire would jump. The a arm has yellow chalk like from pick a part?
Thanks man! I just hope I don't have to invest alot just to make it run around. I've worked on cars before but never a 300zx haha

[RickJC288]

Oh and the fish tail problem when I was under the car yesterday the sway bar had a half inch of a clean gap like when it was fish tailing it cleaned the space that it moves back and forth

[ShiroZ32]

Sounds like its the differential bushings. Mine does the exact same as yours and I've confirmed that my diff bushings are done. Haven't gotten the time to replace them though since she's my daily. But you should check yours out just to make sure

[centralcoaster33]

Hmmm, I've done that dangerous running on jack stands before. But, I'm not sure that is what I'd be looking for this time. I'm suggesting that your sub-frame moves separately from your chassis. Your fishtail and clunk symptoms point to that. How much movement did you witness at the sub-frame bushing locations? So, for movement, you'd see like half an inch of free travel between the sub-frame and the chassis. You should have pretty close to zero movement between these two if the bushings are good.

You can jack up the car and notice the movement at the point before the wheels start to leave the ground. Or, with the car on jack stands, the sub-frame is hanging from it's 4 mounting points (with bushings), so you put the floor jack under the sub-frame and move that up until it starts to lift the car. Or, you could take the nut and washer off of the sub-frame mount and look at the actual bushing to see what's left of it. Basically, the center core would have separated from the outer cylinder. The front ones tend to be more blown than the rear ones in my experience, so check one front and one rear.

PS - the clean spots on the sway don't surprise me.

[RickJC288]

Okay awesome!! Yeah I've been stressing out lately cause I just got it and as soon as I got home all I noticed more and more as miles came on! I wanted some help from the pros and those with personal experience before I take it in and let's say the mechanic screws me over with 5 things! I'm having a friend of a friend who's specializes in 240s 300s and all the Zs check for me and show me everything first hand to learn about it and fix that problem! I reallt appreciate the help amd feed back! It means alot! But yeah so far the carrier bearing or the traight seem to be the problem right now because nothing is coming from the axle and it's more underneath the center console.

[RickJC288]

Sorry for all the typos lol

[RickJC288]

I jacked the car up and put it in gear while a buddy checked and it didn't knock at all so it might be the carrier or traight from the axle cause the more I drive the more I notice it's in the middle of my console area! I posted this same thing on a different page I things the general section and they said it's possibly the carrier or traight for sure. So I'm hoping it's that and nothing major haha
I appreciate the help and feed back! It's extremely helpful man!

[Rogue One]

Merged duplicate threads. Please note that cross-posting (i.e. posting the same topic in more than one forum board) is frowned upon. It's confusing, and often counterproductive.